How can I use PHP to dynamically publish an ical file to be read by Google Calendar

Question

Any Google search on PHP ical just brings up phpicalendar and how to parse or read IN ical files  I just want to write a PHP file that pulls events from my database and writes them out in ical format   My problem is I can t find anywhere that will answer two questions    What is the exact ical format  including headers  file format  footers  etc   In other words  what does the file have to have  exactly  in order to be properly read in by Google Calendar  etc   If I build this file using a  php extension  how do I publish it as ical  Do I have to write to a new  ics file  Or will Google Calendar etc  read a  php file as ical so long as the contents are in the correct format   Much like a style css php file will be read as a CSS file if the contents are actually CSS  etc     Any help you all can give or point me to will be greatly appreciated

User · Answer

A note of personal experience in addition to both Stefan Gehrig's answer and Dave None's answer (and mmmshuddup's reply):

I was having validation problems using both \n and PHP_EOL when I used the ICS validator at http://severinghaus.org/projects/icv/

I learned I had to use \r\n in order to get it to validate properly, so this was my solution:

function dateToCal($timestamp) {
  return date('Ymd\Tgis\Z', $timestamp);
}

function escapeString($string) {
  return preg_replace('/([\,;])/','\\\$1', $string);
}    

    $eol = "\r\n";
    $load = "BEGIN:VCALENDAR" . $eol .
    "VERSION:2.0" . $eol .
    "PRODID:-//project/author//NONSGML v1.0//EN" . $eol .
    "CALSCALE:GREGORIAN" . $eol .
    "BEGIN:VEVENT" . $eol .
    "DTEND:" . dateToCal($end) . $eol .
    "UID:" . $id . $eol .
    "DTSTAMP:" . dateToCal(time()) . $eol .
    "DESCRIPTION:" . htmlspecialchars($title) . $eol .
    "URL;VALUE=URI:" . htmlspecialchars($url) . $eol .
    "SUMMARY:" . htmlspecialchars($description) . $eol .
    "DTSTART:" . dateToCal($start) . $eol .
    "END:VEVENT" . $eol .
    "END:VCALENDAR";

    $filename="Event-".$id;

    // Set the headers
    header('Content-type: text/calendar; charset=utf-8');
    header('Content-Disposition: attachment; filename=' . $filename);

    // Dump load
    echo $load;

That stopped my parse errors and made my ICS files validate properly.

User · Answer

Maybe a little late  but here s a link to the actual specification  http   tools ietf org html rfc55451

User · Answer

Exact ical format  http   www ietf org rfc rfc2445 txt According to the spec  it has to end in  ics   Edit  actually I m not sure - line 6186 gives an example in  ics naming format  but it also states you can use url parameters  I don t think it matters  so long as the MIME type is correct   Edit  Example from wikipedia  http   en wikipedia org wiki ICalendar  BEGIN VCALENDAR VERSION 2 0 PRODID -  hacksw handcal  NONSGML v1 0  EN BEGIN VEVENT DTSTART 19970714T170000Z DTEND 19970715T035959Z SUMMARY Bastille Day Party END VEVENT END VCALENDAR   MIME type is configured on the server

User · Answer

This should be very simple if Google Calendar does not require the   ics-extension  which will require some URL rewriting in the server     ical    BEGIN VCALENDAR VERSION 2 0 PRODID -  hacksw handcal  NONSGML v1 0  EN BEGIN VEVENT UID     md5 uniqid mt rand    true       yourhost test DTSTAMP     gmdate  Ymd    T   gmdate  His      Z DTSTART 19970714T170000Z DTEND 19970715T035959Z SUMMARY Bastille Day Party END VEVENT END VCALENDAR      set correct content-type-header header  Content-type  text calendar  charset utf-8    header  Content-Disposition  inline  filename calendar ics    echo  ical  exit    That s essentially all you need to make a client think that you re serving a iCalendar file  even though there might be some issues regarding caching  text encoding and so on  But you can start experimenting with this simple code

User · Answer

Make sure you format the string like this or it wont work    content    BEGIN VCALENDAR n                VERSION 2 0 n                PRODID -  hacksw handcal  NONSGML v1 0  EN n                BEGIN VEVENT n                UID   uniqid     n                DTSTAMP    time   n                DTSTART    time   n                DTEND    time   n                SUMMARY    summary   n                END VEVENT n                END VCALENDAR

User · Answer

There is an excellent eluceo ical package that allows you to easily create ics files   Here is an example usage from docs      1  Create new calendar  vCalendar   new  Eluceo iCal Component Calendar  www example com        2  Create an event  vEvent   new  Eluceo iCal Component Event     vEvent- gt setDtStart new  DateTime  2012-12-24      vEvent- gt setDtEnd new  DateTime  2012-12-24      vEvent- gt setNoTime true    vEvent- gt setSummary  Christmas        Adding Timezone  optional   vEvent- gt setUseTimezone true       3  Add event to calendar  vCalendar- gt addComponent  vEvent       4  Set headers header  Content-Type  text calendar  charset utf-8    header  Content-Disposition  attachment  filename  cal ics         5  Output echo  vCalendar- gt render

User · Answer

http   www kanzaki com docs ical  has a slightly more readable version of the older spec  It helps as a starting point - many things are still the same  Also on my site  I have  Some lists of useful resources  see sidebar bottom right  on  ical Spec RFC 5545 ical Testing Resources   Some notes recorded on my journey working with  ics over the last few years  In particular  you may find this repeating events  cheatsheet  to be useful    ics areas that need careful handling    all day  events types of dates  timezone  UTC  or local  floating   - nb to understand distinction interoperability of recurrence rules

[php] How can I use PHP to dynamically publish an ical file to be read by Google Calendar?

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